Last week, it was revealed that Machine Head frontman Robb Flynn would undergo gallbladder surgery to alleviate the pain he had been having from gallstones in hopes he could be recovered in time for the band's upcoming tour that begins May 25.

It appears the recovery is going well. The band has posted video footage that you can check out below that shows them rehearsing. Machine Head play "Clenching the Fists of Dissent" and also run through "Days Turn Blue to Grey" for the first time in 10 years as they prepare to embark on a worldwide tour in support of their latest album Bloodstone and Diamonds.

The first date is in Mexico, then they head to South America, New Zealand, Australia, Japan, Thailand and Taiwan before wrapping the tour up July 5. Machine Head kick off a European tour in late August that will keep them on the road through early October. For all their dates, go here.

In an interview with Loudwire, Flynn talked about his honesty and outspokenness: "The bands that I grew up loving, they tended to be a little outspoken and have opinions and now that was inspiring to me. I grew up in what I consider to be the golden era of thrash and right in my backyard was this amazing musical movement that had happened. I grew up in the bay area, I was a 15-year-old kid and I would go and see bands like Metallica, Exodus, Slayer opening for people and playing to 400 people in clubs. Megadeth and stuff like that."

Flynn continues, "Right around that same time this amazing punk movement came out with bands like DRI, the Dead Kennedys and UK punk like Discharge and at the same time was this hip-hop movement with bands like NWA, Public Enemy. All these very provocative bands that stood on or something. They agitated and they weren’t trying to be liked [laughs] they were trying to change the world. In so many ways, all of those three musical movements really helped shaped what became Machine Head. We try and carry that same spirit and fly that same flag."